A chest x-ray will be given to determine the size of the heart and the blood vessels supplying blood to the lungs.

Canadian genetic testing guidelines and recommendations for individuals diagnosed with HCM are as follows:

- The main purpose of genetic testing is for screening family members.

- According to the results, at-risk relatives may be encouraged to undergo extensive testing.

- Genetic testing is not meant for confirming a diagnosis.

- If the diagnosed individual has no relatives that are at risk, then genetic testing is not required.

- Genetic testing is not intended for risk assessment or treatment decisions.

- Evidence only supports clinical testing in predicting the progression and risk of developing complications of HCM.

For individuals "suspected" of having HCM:

- Genetic testing is not recommended for determining other causes of left ventricular hypertrophy (such as "athlete's heart", hypertension, and cardiac amyloidosis).

- HCM may be differentiated from other hypertrophy-causing conditions using clinical history and clinical testing.

A color flow and doppler imaging is used to help confirm the presence as well as evaluate the severity of ASD and MS.

AVSDs can be detected by cardiac auscultation; they cause atypical murmurs and loud heart tones. Confirmation of findings from cardiac auscultation can be obtained with a cardiac ultrasound (echocardiography - less invasive) and cardiac catheterization (more invasive).

Tentative diagnosis can also be made in utero via fetal echocardiogram. An AVSD diagnosis made before birth is a marker for Down syndrome, although other signs and further testing are required before any definitive confirmation of either can be made.

Hypoplastic left heart syndrome can be diagnosed prenatally or after birth via echocardiography. Typical findings include a small left ventricle and aorta, abnormalities of the mitral and aortic valves, retrograde flow in the transverse arch of the aorta, and left-to-right flow between the atria. It is often recognized during the second trimester of pregnancy, between 18 and 24 weeks' gestation.

Congenital heart defects are now diagnosed with echocardiography, which is quick, involves no radiation, is very specific, and can be done prenatally.

Before more sophisticated techniques became available, chest x-ray was the definitive method of diagnosis. The abnormal "coeur-en-sabot" (boot-like) appearance of a heart with tetralogy of Fallot is classically visible via chest x-ray, although most infants with tetralogy may not show this finding. Absence of interstitial lung markings secondary to pulmonary oligaemia are another classic finding in tetralogy, as is the pulmonary bay sign.

ARVD is an autosomal dominant trait with reduced penetrance. Approximately 40–50% of ARVD patients have a mutation identified in one of several genes encoding components of the desmosome, which can help confirm a diagnosis of ARVD. Since ARVD is an autosomal dominant trait, children of an ARVD patient have a 50% chance of inheriting the disease causing mutation. Whenever a mutation is identified by genetic testing, family-specific genetic testing can be used to differentiate between relatives who are at-risk for the disease and those who are not. ARVD genetic testing is clinically available.

In regards to the diagnosis of pulmonary atresia the body requires oxygenated blood for survival. pulmonary atresia is not threatening to a developing fetus however, because the mother's placenta provides the needed oxygen since the baby's lungs are not yet functional. Once the baby is born its lungs must now provide the oxygen needed for survival, but with pulmonary atresia there is no opening on the pulmonary valve for blood to get to the lungs and become oxygenated. Due to this, the newborn baby is blue in color and pulmonary atresia can usually be diagnosed within hours or minutes after birth.

The diagnosis of pulmonary atresia can be done via the following exams/methods: an echocardiogram, chest x-ray, EKG and an exam to measure the amount of in the body.

Hypoplastic right heart syndrome is less common than hypoplastic left heart syndrome which occurs in 4 out of every 10,000 births. [3].

This rare anomaly requires prenatal diagnosis since it needs immediate and emergency treatment. Pregnant women whose pregnancy is complicated with this anomaly should be referred to a level 3 hospital with pediatric cardiology and pediatric cardiothoracic surgical team.[3]

It can be associated with aortic stenosis.

A VSD can be detected by cardiac auscultation. Classically, a VSD causes a pathognomonic holo- or pansystolic murmur. Auscultation is generally considered sufficient for detecting a significant VSD. The murmur depends on the abnormal flow of blood from the left ventricle, through the VSD, to the right ventricle. If there is not much difference in pressure between the left and right ventricles, then the flow of blood through the VSD will not be very great and the VSD may be silent. This situation occurs a) in the fetus (when the right and left ventricular pressures are essentially equal), b) for a short time after birth (before the right ventricular pressure has decreased), and c) as a late complication of unrepaired VSD. Confirmation of cardiac auscultation can be obtained by non-invasive cardiac ultrasound (echocardiography). To more accurately measure ventricular pressures, cardiac catheterization, can be performed.

A less invasive method for detecting a PFO or other ASDs than transesophagal ultrasound is transcranial Doppler with bubble contrast. This method reveals the cerebral impact of the ASD or PFO.

d-TGA can sometimes be diagnosed in utero with an ultrasound after 18 weeks gestation. However, if it is not diagnosed in utero, cyanosis of the newborn (blue baby) should immediately indicate that there is a problem with the cardiovascular system. Normally, the lungs are examined first, then the heart is examined if there are no apparent problems with the lungs. These examinations are typically performed using ultrasound, known as an echocardiogram when performed on the heart. Chest x-rays and electrocardiograms (EKG) may also be used in reaching or confirming a diagnosis; however, an x-ray may appear normal immediately following birth. If d-TGA is accompanied by both a VSD and pulmonary stenosis, a systolic murmur will be present.

On the rare occasion (when there is a large VSD with no significant left ventricular outflow tract obstruction), initial symptoms may go unnoticed, resulting in the infant being discharged without treatment in the event of a hospital or birthing center birth, or a delay in bringing the infant for diagnosis in the event of a home birth. On these occasions, a layperson is likely not to recognize symptoms until the infant is experiencing moderate to serious congestive heart failure (CHF) as a result of the heart working harder in a attempt to increase oxygen flow to the body; this overworking of the heart muscle eventually leads to hypertrophy and may result in cardiac arrest if left untreated.

For proper diagnosis of situs ambiguous, cardiac and non-cardiac features must be evaluated. Diagnostic criteria for atrial isomerism includes observation of symmetry of thoracic visceral organs upon echocardiogram, arrhythmia upon electrocardiogram, and chest x-ray for confirmation of the heart's location across the left-right axis. In addition, a series of gastrointestinal tests can be conducted for observation of intestinal malrotation, as well as a scan of the liver and spleen for biliary function.

With a series of operations or even a heart transplant, a newborn can be treated but not be cured. Young individuals who have undergone reconstructive surgery must refer to a cardiologist who is experienced in congenital heart diseases, "Children with HLHS are at an increased level for developing endocarditis." Kids that have been diagnosed with HRHS must limit the physical activity they participate in to their own endurance level.

In transthoracic echocardiography, an atrial septal defect may be seen on color flow imaging as a jet of blood from the left atrium to the right atrium.

If agitated saline is injected into a peripheral vein during echocardiography, small air bubbles can be seen on echocardiographic imaging. Bubbles traveling across an ASD may be seen either at rest or during a cough. (Bubbles only flow from right atrium to left atrium if the right atrial pressure is greater than left atrial). Because better visualization of the atria is achieved with transesophageal echocardiography, this test may be performed in individuals with a suspected ASD which is not visualized on transthoracic imaging.

Newer techniques to visualize these defects involve intracardiac imaging with special catheters typically placed in the venous system and advanced to the level of the heart. This type of imaging is becoming more common and involves only mild sedation for the patient typically.

If the individual has adequate echocardiographic windows, use of the echocardiogram to measure the cardiac output of the left ventricle and the right ventricle independently is possible. In this way, the shunt fraction can be estimated using echocardiography.

Although its cause is poorly understood, situs ambiguous has been linked to family history of malformations and maternal cocaine use, suggesting both genetic and environmental factors play a role. Several genes in the TGF-beta pathway, which controls left-right patterning of viseral organs across the body axis, have been indicated in sporadic and familial cases of atrial isomerism.

There does not appear to be a screening method for prevention of heterotaxy syndrome. However, genetic testing in family members that display atrial isomerism or other cardiac malformations may help to discern risk for additional family members, especially in X-linked causes of heterotaxy syndrome.

Although there are several classifications for VSD, the most accepted and unified classification is that of Congenital Heart Surgery Nomenclature and Database Project.

The classification is based on the location of the VSD on the right ventricular surface of the inter ventricular septum and is as follows:

With simple d-TGA, if the foramen ovale and ductus arteriosus are allowed to close naturally, the newborn will likely not survive long enough to receive corrective surgery. With complex d-TGA, the infant will fail to thrive and is unlikely to survive longer than a year if corrective surgery is not performed. In most cases, the patient's condition will deteriorate to the point of inoperability if the defect is not corrected in the first year.

While the foramen ovale and ductus arteriosus are open after birth, some mixing of red and blue blood occurs allowing a small amount of oxygen to be delivered to the body; if ASD, VSD, PFO, and/or PDA are present, this will allow a higher amount of the red and blue blood to be mixed, therefore delivering more oxygen to the body, but can complicate and lengthen the corrective surgery and/or be symptomatic.

Modern repair procedures within the ideal timeframe and without additional complications have a very high success rate.

Tet spells may be treated with beta-blockers such as propranolol, but acute episodes require rapid intervention with morphine or intranasal fentanyl to reduce ventilatory drive, a vasopressor such as phenylephrine, or norepinephrine to increase systemic vascular resistance, and IV fluids for volume expansion.

Oxygen (100%) may be effective in treating spells because it is a potent pulmonary vasodilator and systemic vasoconstrictor. This allows more blood flow to the lungs by decreasing shunting of deoxygenated blood from the right to left ventricle through the VSD. There are also simple procedures such as squatting and the knee chest position which increase systemic vascular resistance and decrease right-to-left shunting of deoxygenated blood into the systemic circulation.

PDA is usually diagnosed using noninvasive techniques. Echocardiography (in which sound waves are used to capture the motion of the heart) and associated Doppler studies are the primary methods of detecting PDA. Electrocardiography (ECG), in which electrodes are used to record the electrical activity of the heart, is not particularly helpful as no specific rhythms or ECG patterns can be used to detect PDA.

A chest X-ray may be taken, which reveals overall heart size (as a reflection of the combined mass of the cardiac chambers) and the appearance of blood flow to the lungs. A small PDA most often accompanies a normal-sized heart and normal blood flow to the lungs. A large PDA generally accompanies an enlarged cardiac silhouette and increased blood flow to the lungs.

Right ventricular angiography is considered the gold standard for the diagnosis of ARVD. Findings consistent with ARVD are an akinetic or dyskinetic bulging localized to the infundibular, apical, and subtricuspid regions of the RV. The specificity is 90%; however, the test is observer dependent.

The prognosis for pulmonary atresia varies for every child, if the condition is left uncorrected it may be fatal, but the prognosis has greatly improved over the years for those with pulmonary atresia. Some factors that affect how well the child does include how well the heart is beating, and the condition of the blood vessels that supply the heart. Most cases of pulmonary atresia can be helped with surgery, if the patient's right ventricle is exceptionally small, many surgeries will be needed in order to help stimulate normal circulation of blood to the heart.If uncorrected, babies with this type of congenital heart disease may only survive for the first few days of life. Many children with pulmonary atresia will go on to lead normal lives, though complications such as endocarditis, stroke and seizures are possible.

95% of untreated infants with HLHS die in the first weeks of life.

Early survival has improved since the introduction of the Norwood procedure. Since there are no long-term studies of HLHS adults, statistics are usually derived from post-Fontan patients; it is estimated that 70% of HLHS patients will reach adulthood.

As is true for patients with other types of heart defects involving malformed valves, HLHS patients run a high risk of endocarditis, and must be monitored by a cardiologist for the rest of their lives to check on their heart function.

Heart transplantation may be indicated, typically after Fontan completion. One multi-center study (of patients undergoing the Fontan from 1993-2001) reported a 76% 1-year survival rate in patients who survived to transplant.

Although HCM may be asymptomatic, affected individuals may present with symptoms ranging from mild to critical heart failure and sudden cardiac death at any point from early childhood to seniority. HCM is the leading cause of sudden cardiac death in young athletes in the United States, and the most common genetic cardiovascular disorder. One study found that the incidence of sudden cardiac death in young competitive athletes declined in the Veneto region of Italy by 89% since the 1982 introduction of routine cardiac screening for athletes, from an unusually high starting rate. As of 2010, however, studies have shown that the incidence of sudden cardiac death, among all people with HCM, has declined to one percent or less. Screen-positive individuals who are diagnosed with cardiac disease are usually told to avoid competitive athletics.

HCM can be detected with an echocardiogram (ECHO) with 80%+ accuracy, which can be preceded by screening with an electrocardiogram (ECG) to test for heart abnormalities. Cardiac magnetic resonance imaging (CMR), considered the gold standard for determining the physical properties of the left ventricular wall, can serve as an alternative screening tool when an echocardiogram provides inconclusive results. For example, the identification of segmental lateral ventricular hypertrophy cannot be accomplished with echocardiography alone. Also, left ventricular hypertrophy may be absent in children under thirteen years of age. This undermines the results of pre-adolescents’ echocardiograms. Researchers, however, have studied asymptomatic carriers of an HCM-causing mutation through the use of CMR and have been able to identify crypts in the interventricular septal tissue in these people. It has been proposed that the formation of these crypts is an indication of myocyte disarray and altered vessel walls that may later result in the clinical expression of HCM. A possible explanation for this is that the typical gathering of family history only focuses on whether sudden death occurred or not. It fails to acknowledge the age at which relatives suffered sudden cardiac death, as well as the frequency of the cardiac events. Furthermore, given the several factors necessary to be considered at risk for sudden cardiac death, while most of the factors do not have strong predictive value individually, there exists ambiguity regarding when to implement special treatment.

Treatment is surgical and involves closure of the atrial and ventricular septal defects and restoration of a competent left AV valve as far as is possible. Open surgical procedures require a heart-lung machine and are done with a median sternotomy. Surgical mortality for uncomplicated ostium primum defects in experienced centers is 2%; for uncomplicated cases of complete atrioventricular canal, 4% or less. Certain complications such as tetralogy of Fallot or highly unbalanced flow across the common AV valve can increase risk significantly.

Infants born with AVSD are generally in sufficient health to not require immediate corrective surgery. If surgery is not required immediately after birth, the newborn will be closely monitored for the next several months, and the operation held-off until the first signs of lung distress or heart failure. This gives the infant time to grow, increasing the size of, and thereby the ease of operation on, the heart, as well as the ease of recovery. Infants will generally require surgery within three to six months, however, they may be able to go up to two years before the operation becomes necessary, depending on the severity of the defect.